“…These infections are largely endemic and have an overall infection rate that ranges from 1,8 to 13,5 infections per 1000 resident care days (Strausbaugh LJ & Al, 2000). The variability of prevalence (Cohen E & Al, 1979;Garibaldi R & Al, 1981;Standfast SJ & Al, 1984;Setia U & Al, 1985;Scheckler W & Peterson P, 1986;Alvarez S & Al, 1988;Magaziner J & Al, 1991;Steinmiller A & Al, 1991;Eikelenboom-Boskamp A & Al, 2011) and incidence (Magnussen M & Robb S, 1980;Farber BF & Al, 1984;Nicolle LE & Al, 1984;Franson T & Al, 1986;Scheckler W & Peterson P, 1986;Viahov D & Al, 1987;Alvarez S & Al, 1988;Schicker JM & Al, 1988;Hoffman N & Al, 1990;Jacobson C & Strausbaugh LJ, 1990;Darnowsky S & Al, 1991;Jackson M & Al, 1992) rate of infections, reflects differences in patients populations in different study institutions, as well as differing surveillance definitions and methods for case ascertainment .…”